This invention relates to adjustable threshold assemblies of the general type disclosed in U.S. Pat. Nos. 5,010,690 and 5,230,181 which issued to the assignee of the present invention. In such an assembly, an elongated extruded aluminum sill member is supported by and attached to a wood base member, and a longitudinally extending wood trim member is attached to the inner edge of the base member. The sill, base and trim members cooperate to define a longitudinally extending cavity which receives a vertically adjustable rail member in the form of a wood or inverted extruded aluminum channel. The rail member carries longitudinally spaced captive screws which may be threaded into a portion of the aluminum sill member within the recess, as shown in the above patents. It is also known for the captive screws to be threaded into tubular T-nuts which are inserted into corresponding holes within the wood base member and flared at the bottom of the nuts, for example, as disclosed in U.S. Pat. No. 3,967,412.
Sometimes it is desirable for the threshold assembly to extend under a fixed jamb member or mull ion and also under one or more side lites or panels, for example, as disclosed in U.S. Pat. Des. No. 110,452 and U.S. Pat. No. 4,945,680. When one or more stationary or fixed side panels are used on one side or both sides of a moveable or pivotable door, sometimes separate aluminum sill members are used under the door and each side panel, and the mullion or jamb between the door and each side panel is used to cover the joint between the separate sill members. The sill member under the fixed side panel has also been provided with an upwardly projecting and integrally extruded aluminum flange which forms a corner seat for the fixed side panel. Caulking is used between the flange and the panel to form a water-tight seal.
When a single extruded aluminum sill member extends under the door and each side panel, it is known to use an extruded vinyl strip under the side panel. The vinyl strip is attached to the aluminum sill member and the supporting wood base member, and caulking is used between the bottom of the side panel and the vinyl strip to form a water-tight seal. It is a well known problem that most caulking materials become dry and hard after a period of time and develop cracks which destroy the seal provided by the caulking material.